P-POSSUM Score
Determines operative mortality risk for general emergency or elective surgery.
Refer to the text below the calculator for more information about the P-POSSUM score.
The Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) is the modified version of the original POSSUM Score that retains the same variables but uses a different mortality predictor equation.
The score evaluates mortality risk in patients due for emergency or elective surgery and should be computed at time of surgery, based on readily available clinical data.
The score is not indicated for trauma patients nor can be used in predicting mortality after trauma surgery.
The P-POSSUM score consists of two components, a physiological score and an operative score that are used to compute the operative mortality risk:
LogeR/1-R = -9.065 + 0.1692 x Physiological Score + 0.155 x Operative Severity Score
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The P-POSSUM Score explained
The Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) is the modified version of the original POSSUM Score that retains the same variables but uses a different mortality predictor equation.
The score evaluates mortality risk in patients due for emergency or elective surgery and should be computed at time of surgery, based on readily available clinical data.
The score is not indicated for trauma patients nor can be used in predicting mortality after trauma surgery.
In 1998, Prytherch et al. developed a more accurate scoring equation for the mortality component, whilst retaining the 12 physiological score parameters and 6 operation severity parameters.
This came following the need to adjust the logistic regression analysis used in POSSUM scoring to better predict mortality.
The study by Prytherch et al. found that the original POSSUM logistic regression equation for mortality overpredicted the overall risk of death by more than twofold (in patients at lowest risk <5% overpredicted by more than sevenfold).
The study collected data from 10,000 general surgical interventions, the first 2,500 being used as a training set to produce the modified P-POSSUM predictor equation, whilst on the remainder, the predictive properties of the score were tested. The P-POSSUM equation produced a very close fit with the observed in-hospital mortality.
Physiological Score | ||||
Variable | 1 point | 2 points | 4 points | 8 points |
Age | ≤ 60 | 61-70 | ≥ 71 | |
Cardiac signs Chest X-ray |
Normal Normal |
Cardiac drugs or steroids … |
Oedema; warfarin Borderline cardiomegaly |
Jugular venous pressure Cardiomegaly |
Respiratory signs Chest X-ray |
Normal Normal |
Shortness of breath on exertion Mild chronic obstructive airway disease |
Shortness of breath on stairs Moderate chronic obstructive airway disease |
Shortness of breath at rest Any other change |
Systolic blood pressure (mmHg) | 110-130 | 131-170 or 100-109 | ≥ 171 or 90-99 | ≤ 89 |
Pulse (beats/min) | 50-80 | 81-100 or 40-49 | 101-120 | ≥ 121 or ≤ 39 |
Glasgow coma score | 15 | 12-14 | 9-11 | ≤ 8 |
Urea nitrogen (mmol/L) | < 7.5 | 7.6-10 | 10.1-15 | ≥ 15.1 |
Sodium (mEq/L) | > 136 | 131-135 | 126-130 | ≤ 125 |
Potassium (mEq/L) | 3.5-5 | 3.2-3.4 or 5.1-5.3 | 2.9-3.1 or 5.4-5.9 | ≤ 2.8 or ≥ 6 |
Haemoglobin (g/dL) | 13-16 | 11.5-12.9 or 16.1-17 | 10-11.4 or 17.1-18 | ≤ 9.9 or ≥ 18.1 |
WCC (x1012/L) | 4-10 | 10.1-20 or 3.1-3.9 | ≥ 20.1 or ≤ 3 | |
Electrocardiogram | Normal | AF (60-90) | Any other change |
Operative Score | ||||
Variable | 1 point | 2 points | 4 points | 8 points |
Operative magnitude | Minor | Intermediate | Major | Major+ |
No. of operations within 30 days | 1 | 2 | > 2 | |
Blood loss per operation (mL) | < 100 | 101-500 | 501-999 | > 1000 |
Peritoneal contamination | No | Serious | Local pus | Free Bowel content, pus or blood |
Presence of malignancy | No | Primary cancer only | Node metastases | Distant metastases |
Timing of operation | Elective | Emergency resuscitation possible, operation <24h | Emergency immediate operation <2h |
The P-POSSUM equation for mortality risk:
LogeR/1-R = -9.065 + 0.1692 x Physiological Score + 0.155 x Operative Severity Score
Examples of magnitude for general surgery:
- Minor: hernia, varicose vein, minor perianal surgery, scrotal surgery, minor transurethral resection of tumor, excision of large subcutaneous lesion;
- Intermediate: open cholecystectomy, laparoscopic cholecystectomy, appendectomy, excision of lesion requiring grafting or minor excision, minor amputation, thyroid lobectomy;
- Major: laparotomy and small-bowel resection, colonic resection or anterior resection, major amputation, nonaortic vascular surgery, cholecystectomy and exploration of bile duct, total thyroidectomy;
- Major+: abdominoperineal excision of rectum, aortic surgery, whipple resection, radical total gastrectomy;
There are other perioperative morbidity and/or mortality risk predictors available, either for general surgery or for specific diseases and morbidities:
- The Surgical Apgar Score (SAS) offers a morbidity and mortality risk estimation and whilst it is deemed more objective than POSSUM, it is less comprehensive (uses only 3 intraoperative variables) whilst POSSUM uses several more preoperative variables.
- The APACHE II model estimates risk of mortality in intensive care patients.
- The Revised Cardiac Risk Index (RCRI) estimates risk of perioperative cardiac events in patients undergoing heart surgery.
References
Original reference
Prytherch DR et al. POSSUM and Portsmouth POSSUM for predicting mortality. Br J Surg. 1998; 85:1217-20.
Validation
Tran Ba Loc P, du Montcel ST, Duron JJ, et al. Elderly POSSUM, a dedicated score for prediction of mortality and morbidity after major colorectal surgery in older patients. Br J Surg. 2010; 97(3):396‐403.
Other references
Scott, S., Lund, J.N., Gold, S. et al. An evaluation of POSSUM and P-POSSUM scoring in predicting post-operative mortality in a level 1 critical care setting. BMC Anesthesiol 14, 104 (2014).
Specialty: Emergency
No. Of Variables: 18
Year Of Study: 1998
Abbreviation: P-POSSUM
Article By: Denise Nedea
Published On: June 1, 2020 · 12:00 AM
Last Checked: June 1, 2020
Next Review: June 1, 2025